/
appdata.go
114 lines (90 loc) · 3.18 KB
/
appdata.go
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// Copyright 2020 New Relic Corporation. All rights reserved.
// SPDX-License-Identifier: Apache-2.0
package cat
import (
"bytes"
"encoding/json"
"errors"
"github.com/newrelic/go-agent/internal/jsonx"
)
// AppDataHeader represents a decoded AppData header.
type AppDataHeader struct {
CrossProcessID string
TransactionName string
QueueTimeInSeconds float64
ResponseTimeInSeconds float64
ContentLength int64
TransactionGUID string
}
var (
errInvalidAppDataJSON = errors.New("invalid transaction data JSON")
errInvalidAppDataCrossProcessID = errors.New("cross process ID is not a string")
errInvalidAppDataTransactionName = errors.New("transaction name is not a string")
errInvalidAppDataQueueTimeInSeconds = errors.New("queue time is not a float64")
errInvalidAppDataResponseTimeInSeconds = errors.New("response time is not a float64")
errInvalidAppDataContentLength = errors.New("content length is not a float64")
errInvalidAppDataTransactionGUID = errors.New("transaction GUID is not a string")
)
// MarshalJSON marshalls an AppDataHeader as raw JSON.
func (appData *AppDataHeader) MarshalJSON() ([]byte, error) {
buf := bytes.NewBufferString("[")
jsonx.AppendString(buf, appData.CrossProcessID)
buf.WriteString(",")
jsonx.AppendString(buf, appData.TransactionName)
buf.WriteString(",")
jsonx.AppendFloat(buf, appData.QueueTimeInSeconds)
buf.WriteString(",")
jsonx.AppendFloat(buf, appData.ResponseTimeInSeconds)
buf.WriteString(",")
jsonx.AppendInt(buf, appData.ContentLength)
buf.WriteString(",")
jsonx.AppendString(buf, appData.TransactionGUID)
// The mysterious unused field. We don't need to round trip this, so we'll
// just hardcode it to false.
buf.WriteString(",false]")
return buf.Bytes(), nil
}
// UnmarshalJSON unmarshalls an AppDataHeader from raw JSON.
func (appData *AppDataHeader) UnmarshalJSON(data []byte) error {
var ok bool
var v interface{}
if err := json.Unmarshal(data, &v); err != nil {
return err
}
arr, ok := v.([]interface{})
if !ok {
return errInvalidAppDataJSON
}
if len(arr) < 7 {
return errUnexpectedArraySize{
label: "unexpected number of application data elements",
expected: 7,
actual: len(arr),
}
}
if appData.CrossProcessID, ok = arr[0].(string); !ok {
return errInvalidAppDataCrossProcessID
}
if appData.TransactionName, ok = arr[1].(string); !ok {
return errInvalidAppDataTransactionName
}
if appData.QueueTimeInSeconds, ok = arr[2].(float64); !ok {
return errInvalidAppDataQueueTimeInSeconds
}
if appData.ResponseTimeInSeconds, ok = arr[3].(float64); !ok {
return errInvalidAppDataResponseTimeInSeconds
}
cl, ok := arr[4].(float64)
if !ok {
return errInvalidAppDataContentLength
}
// Content length is specced as int32, but not all agents are consistent on
// this in practice. Let's handle it as int64 to maximise compatibility.
appData.ContentLength = int64(cl)
if appData.TransactionGUID, ok = arr[5].(string); !ok {
return errInvalidAppDataTransactionGUID
}
// As above, we don't bother decoding the unused field here. It just has to
// be present (which was checked earlier with the length check).
return nil
}